Chapter 1: Understanding ISDN and the ISU 512
2
ISU 512 User Manual
61202.086L1-1
The ISU 512 transmits data over an RS-530 or V.35 interface, selectable from
the front panel. The ISU 512 performs at synchronous data transfer rates of 56
kbps to 512 kbps. At rates over 64 kbps, the BONDING Mode 1 inverse mul-
tiplexing protocol synchronizes data over up to eight 64 kbps B channels. By
supporting BONDING, the ISU 512 interoperates with other BONDING-com-
patible inverse multiplexers and ISDN terminal adapters. The ISU 512 is in-
tended to support the transfer of data and images over ISDN.
The ISU 512 has four RJ-45 jacks available on the rear panel for network con-
nection (see Figure 1-1).
Figure 1-1
ISU 512 Rear Panel
The ISU 512 (U interface) also supports a leased digital connection that allows
data to be transferred at up to 512 kbps. This type of service is a permanent
connection between end points and is sometimes referred to as a leased con-
nection, a dedicated connection, a nailed-up connection, a private circuit, or a
limited distance modem (LDM) connection. Leased connection or leased ap-
plication is used in this manual to represent these types of services.
The ISU 512 can be configured using the front panel keypad, remotely over the
ISDN line, or using a VT 100 terminal operating at 9600 bps (8 data bits, 1 stop
bit, no parity). The VT 100 terminal interface is connected to the ISU 512
through the Chain In port on the rear of the unit. See the section
VT 100 Menu
Interface
in Chapter 3 for more information. The front panel keypad and the
terminal interface support test modes, test status, and dialing.
#1
#2
RS366 DIALING PORT
RS530
O
N
O
F
F
90-250 VAC
50/60HZ.15A
IN
#3
V.35
#4
OUT
ISDN IFC
CONTROL/
CHAIN PORT
